As used herein the term “container” is intended to cover containers for distributing foodstuffs, such as boxes, crates or cases for containing e.g. bread, fruit, milk in cartons, meat or the like, and/or containers for distributing medical or pharmaceutical products e.g. from a manufacturer to the retail stage of a distribution chain, the containers being re-useable. Preferably, but not exclusively, such containers are of the type comprising openings, such as a grating-like structure, in one or more sidewalls and/or in a bottom. Furthermore, such containers may be of the collapsible type, e.g. of the type having collapsible side walls.
After each use the containers are eventually returned to the manufacturer. Before being used again, the containers must due to hygienic requirements be cleaned, and are therefore typically washed and thereupon dryed by means of a container drying device, particularly a container drying device according to the invention.
Most known container drying machines are capable of processing only one or very few containers at the time or at most one stack of containers at the time, and thus have very low capacities, which results in a time consuming, energy consuming and expensive cleaning procedure.
Another type of container drying machine is known from JP 2004-101075 A, which describes an apparatus for centrifugal drying of stacks of containers in which the stacks of containers are loaded one at the time through a first side of the apparatus and are unloaded one at the time through a second side of the apparatus extending perpendicularly to the first side of the apparatus. The apparatus comprises four positioning maintaining structures arranged eccentrically with respect to the axis of rotation of the apparatus and radially equidistant with respect to each other. When placed in the apparatus, the stacks of containers are initially arranged pairwise either end to end or corner to corner in extension of each other on opposite sides of the center of rotation. As described in JP 2004-101075 A, the position maintaining structures provide for such an arrangement of the containers during rotation of the apparatus that the largest centrifugal forces are acting on the corners of the apparatus.
Furthermore, EP 2 136 171 A2 describes a centrifugal machine for drying stacks of containers, the machine comprising a plurality of compartments arranged eccentrically with respect to the center of rotation of the machine and disposed radially with respect to the center of rotation and angularly equidistant with respect to each other. The stacks of containers are loaded and unloaded one at the time into and out of, respectively, the machine through a designated opening in a central part of a top side of the machine. When placed in the machine, the stacks of containers are arranged pairwise end to end in extension of each other on opposite sides of the center of rotation.
These types of container drying machines may dry several stacks of containers simultaneously, but nevertheless have several drawbacks. Firstly, only one stack of containers may be loaded into or unloaded from the machine at the time. Thereby, the capacity of the machine, i.e. the number of containers treated per time unit, has a relatively low upper limit, and the cleaning procedure becomes correspondingly more time consuming. Secondly, both the construction of the machines itself, being rather complex and thus correspondingly heavy, and the arrangement of the stacks of containers in the machines result in a high energy consumption and a high exposure of less durable parts of the machine to stress caused by the centrifugal forces acting during rotation of the machine.
Therefore, it is the object of the invention to provide a container drying device which has an improved capacity whilst simultaneously being energy efficient and durable in use.